Temperatures rose from below freezing to the mid 40s on Monday and Tuesday, causing snow and ice to melt before single-digit temperatures Tuesday night froze it into a solid layer of ice.

Peter Banacos, a meteorologist at the National Weather Service in Burlington, Vermont, said Wednesday evening is supposed to bring a mixture of sleet and freezing rain. He said there will be winter weather advisories all over the Adirondacks as ice may build up to a tenth of an inch.

The temperature is forecast to rise again into the 40s on Thursday and Friday before dipping back down into the teens for a dry weekend.

Signs of the warm weather were everywhere Tuesday, from the grubby, dirt-filled snow piles lining the road to the cordoned-off Ice Palace for the Saranac Lake Winter Carnival to the 10-or-so ice fishing tents left on Simond Pond — all that remained of the 1,200 people who were out on the Tupper Lake ice for the Northern Challenge derby over the weekend.

Snow remains on the ground but has melted around the bases of trees Tuesday at the Tupper Lake Cross Country Ski Center. (Enterprise photo — Aaron Cerbone)

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Reason for the warm season

Banacos said the area got the warmest in the Monday-Tuesday overnight hours, reaching as high as 46 degrees before dawn. The record for Feb. 5 is 54 degrees, from 1991. Burlington hit a record high of 53 degrees this week, breaking its former record of 51.

“It’s not all that unusual,” Banacos said. “We get thaw periods every winter.”

He said last week’s polar vortex, which brought lots of snow and cold temperatures across the state, is partially responsible for the warm spell now.

“It’s usually pretty quick moving. So we had some really cold temperatures there for a day or two,” Banacos said. “Usually in response to that, there’s an amplification of the flow pattern. Once that went by, we kind of had a surge of some warmer air coming in from the south.

“Those types of Arctic outbreaks are pretty quick hitting, and you kind of get almost like a corresponding warming track on the backside.”

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Whiteface

Despite the warm weather, nearly 90 percent of the trails at Whiteface and all three peaks were open and skiable as of Tuesday evening. Spokesman Jon Lundin said 76 of the resort’s 86 trails were open and a fresh layer of man-made snow was laid down.

“We drop a lot of snow,” Lundin said. “Fortunately, with the technology of snowmaking today, the high-efficiency, low-energy snow guns were able to make snow quickly and recover quicker than ever before.”

Despite ice forming all over the roads, grass and trees at ground level, Lundin said the mountain had a packed powder and granular surface laid Tuesday morning that kept the trails from being too icy.

Shortly after noon Tuesday, the Cloudsplitter Gondola and the Lookout Triple and Summit Quad lifts were temporarily put on hold for wind hazards.

Lundin said as the weather continues to fluctuate in the coming days, Whiteface staff will focus on maintaining the popular trails and key veins in the trail system.

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Maple sap

The warmer weather has also gotten sap flowing in maple trees.

Adam Wild from Cornell University’s Uihlein Maple Research Forest in Lake Placid said the outdoor laboratory is getting some sap production due to the warm weather, but not enough to start boiling it into syrup yet.

He said the researchers there tapped later this year than they did last year, but they have been tapping earlier and earlier throughout the past decade.

Addison Bickford, who taps maple trees in Rainbow Lake for his Thunderchief brand of syrup, said that it takes four to five days getting out of freezing temperatures for the sap to start running. He said the run is caused by both the sap’s viscosity increasing with the temperature and a complex process of liquids and gasses moving within the trees, and being added or removed from the sap.

There is actually a fair bit of controversy in the scientific community as to what causes this annual phenomenon in sap-producing trees.